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					A Canada Thistle Management Plan for the Anchorage Borough
Gino Graziano, Invasive Plants Instructor, University of Alaska Fairbanks,
Cooperative Extension Service

Canada thistle, or creeping thistle, (Cirsium arvense) is widespread in the city of
Anchorage, yet has a limited distribution in other parts of south-central Alaska. Over
the last year, with support from Forest Health Protection, the Alaska Division of
Agriculture and the Anchorage Cooperative Weed Management Area (CWMA)
developed a Canada Thistle Management Plan for the Anchorage Borough. This plan
describes the distribution and status of Canada thistle infestations in the Anchorage
area, and formulates strategies to increase inventory knowledge, generate public
awareness, manage priority infestations on public lands and increase the
management of infestations on private property.

While Canada thistle is unlikely to be eradicated in Anchorage itself, the city’s
known infestations appear to be manageable in size (fig. 1_ Canada_Thistle_
Essay.jpg). Left unmanaged, Anchorage infestations will serve as a significant source
of propagules to neighboring areas. Forest Health Protection and the State of Alaska
both recognize the potential to successfully manage Canada thistle within the city
and to eradicate it from surrounding areas.

It is likely that Canada thistle was originally introduced to Anchorage by seeds or
rhizomes that were contaminants of nursery products, seed mixtures, hay and
straw. This is evidenced by the concentration of infestations near ornamental
plantings. Now that this thistle has established in parts of Anchorage, it appears that
it is also being spread via contaminated heavy equipment and contaminated soil.

Canada thistle is known to invade a wide range of habitats and is capable of forming
monocultures in the areas that it infests. To date in south-central Alaska, this species
is found primarily on roadsides. However, an infestation was recently discovered
growing in a wet meadow dominated by bluejoint reed grass (Calamagrostis
canadensis) along Chester Creek in Anchorage. Canada thistle is unpalatable to most
animals, and will reduce forage for livestock and wildlife, such as moose and bears
(fig. 2_ Canada_Thistle_Essay.jpg). It has been declared noxious by 35 states (USDA
Plants database 2011), and it is a prohibited noxious weed in Alaska (11 AAC
34.020).

In south-central Alaska, successful management of large, dense infestations of
Canada thistle requires multiple mowing treatments during the growing season,
followed by application of an appropriate systemic herbicide in September. This
mowing-herbicide treatment combination can effectively control infestations of
Canada thistle by preventing vegetative spread and seed dispersal. In autumn, there
is usually a brief window when Canada thistle is still actively photosynthesizing,
while most indigenous vegetation has begun to senesce and is not susceptible to
chemical overspray. Fall applications are complimented by subsequent light frosts,
triggering translocation of the herbicide from the target plant’s leaves to its roots,
resulting in better control of the plant. When thistle is found growing amid
vegetation that can tolerate repeated mowing, frequent mowing alone can
significantly reduce Canada thistle cover.

The deep, extensive root system of Canada thistle makes pulling or digging an
unproductive control practice. However, digging can be effective if excavation of all
roots is possible, typically using large equipment. Such soil must be considered
contaminated, as even small rhizome sections can sprout, leading to new
infestations when the soil is moved. Contaminated soil should only be used as fill in
certain applications, such as beneath parking areas that will be paved. Many people
suspect that Canada thistle continues to be spread in Anchorage via contaminated
fill material.

Several biological control agents are available for Canada thistle management.
However, none of them are very successful in North America because the life cycles
of the biocontrol organisms are not synchronized with the life cycle of the target, so
plants are damaged but not killed. In Anchorage, there does not appear to be
sufficient coverage of Canada thistle on the landscape to support the release of
biocontrol agents at this time. Nonetheless, treating individual infestations with
small-scale biocontrol releases may be possible.

Education and outreach is an integral part of any weed management strategy. It is
important to increase public awareness of Canada thistle: its impact, identification,
how to report new infestations, and control practices. With this knowledge, the
public is empowered to manage infestations on their lands, and to avoid spreading
infestations to new areas. Educating the public about invasive plants leads to
greater acceptance of a variety of different control practices, whether they are
unsightly solarization (tarping) projects, applications of herbicide, or simply
mowing a roadside patch of pretty purple flowers before they set seed.

To date, Canada thistle outreach in Anchorage has primarily involved mailing
informational cards to residences in the Anchorage area and featuring Canada
thistle information in rented advertising space on the sides of public busses. Such
efforts are having a noticeable impact, and, each summer, more and more people
call the Cooperative Extension Service for advice on managing Canada thistle and
other invasive plant species. In addition to continuing household mailing efforts, the
next steps in outreach will be directed at land managers, landscapers and nursery
providers, with a focus on increasing knowledge of Canada thistle and control
strategies.

Overall, the new Canada Thistle Management Plan for the Anchorage Borough
identifies many opportunities for action. Through the implementation of this plan,
the Alaska Division of Agriculture and its partners hope to decrease the risk to
Alaska’s agriculture and natural areas caused by this notorious species.
An update on Elodea, Alaska’s first known non-native freshwater
weed
Nicholas Lisuzzo

In 2009 and 2010, it was brought to the attention of land managers that a
reproducing population of a non-native freshwater weed had been discovered in
Chena Slough near North Pole, Alaska (Figure Alaska_Aquatics_1). The plant was
identified to genus as Elodea, commonly known as waterweed, marking Alaska’s
first detection of a non-native aquatic weed in freshwater ecosystems. As the
community began to react to this discovery, a cold Alaskan winter settled over the
state, leaving many questions about Elodea and its potential impacts unanswered. In
December 2010, a public meeting was hosted by Forest Health Protection staff at
the Alaska Department of Natural Resources office in Fairbanks. As a result of the
meeting, a working group and steering committee were formed and a number of
community members, local, state and federal agencies set out to gather critical
information about Elodea over the course of the next 12 months.
One of the first pieces of new information was the species-level identification of
Elodea in Chena Slough. Initially thought to be E. canadensis, scientists from the
USDA-Forest Service, the National Park Service and the University of Connecticut
collected plant samples from beneath the ice and used floristic and genetic
techniques to identify the species as E. nuttallii. Though closely related to E.
canadensis and almost indistinguishable to the eye, E. nuttallii is considered to be
more aggressive and is currently spreading across Europe, where its range is
believed to be limited by cold weather. The discovery of E. nuttallii in North Pole
signifies a gap of over 2,000 kilometers from its native range in Canada and the
Lower 48 States, and also indicates that this species is able to thrive in colder
climates than previously realized. To date, only specimens from Chena Slough have
been identified to species, and it is possible that other populations in Alaska could
be comprised of one or more Elodea species.
Elodea species primarily reproduce asexually by fragmentation. The delicate stems
easily break into small pieces, each of which is capable of growing into a new plant.
Stem fragments can be spread by boats and boat trailers, and stems are also
commonly sold as aquarium plants. It is suspected that the Chena Slough infestation
may be the result of someone dumping an unwanted aquarium into the stream, and
this is supported by this site’s close proximity to residential neighborhoods and
reports of goldfish in Chena Lake. Floatplanes have also been considered a potential
means of spread for similar plants in New Zealand, and could be an important vector
to rural Alaska. In Europe, Asia and Australia, where Elodea is non-native, it has
caused large-scale changes in freshwater ecosystems. The dense vegetation can
change water quality, increase sedimentation, degrade salmon spawning habitat,
displace native vegetation and act as a physical barrier to fishing and boat travel.
As the snow began to melt in spring, the working group reviewed the scientific
literature and studied potential means of containing or eradicating the Elodea
population in Chena Slough. The working group also created a variety of outreach
materials, and began communicating with communities and natural resource
professionals across the state. The Fairbanks Cooperative Weed Management Area
launched an effort to determine the distribution and extent of Elodea in the
Fairbanks Northstar Borough. With help from the Fairbanks Soil and Water
Conservation District, the US Fish and Wildlife Service and the National Park
Service, crews surveyed almost 200 locations with freshwater habitat thought to be
suitable for Elodea. USDA Forest Service and US Fish and Wildlife Service staff began
to survey lakes and streams on the south side of the Alaska Range (Figures
Alaska_Aquatics_2 and Alaska_Aquatics_3).
By the end of 2011, there was a much clearer picture of the problem. Months of
surveying indicated that the extent and margin of the Chena Slough population was
well-defined. Elodea was found to be present in only three waterbodies in the
Fairbanks/North Pole area: Chena Slough, the Chena River just downstream of its
intersection with the Chena Slough, and the nearby, manmade Chena Lake.
However, surveys farther south discovered that Elodea was much more widely
distributed, with substantial populations detected in Sand, DeLong and Little
Campbell Lakes near Anchorage, and in Eyak, McKinley, and Martin Lakes and
Alaganik Slough near Cordova. The number of affected waterbodies is likely to
increase as awareness grows and surveys continue to document infestations (Figure
Alaska_Aquatics_4).
In other locations where Elodea has been introduced, mowing, suction-dredging,
and herbicides are common forms of control. Control trials were initiated at Chena
Lake in 2011. These treatments involved divers cutting and pulling plants by hand,
and installing benthic barriers (i.e., pieces of opaque fabric) over small Elodea
infestations. These areas will be re-evaluated in 2012, and additional methods, such
as suction-dredging and cutter-dredging, may be tried in the future. Herbicide
applications are often controversial because of potential negative impacts to non-
target organisms.
A multi-community, multi-agency response is being organized to confront the
challenges of Alaska’s first aquatic weed introduction. Important components of an
integrated control strategy will include public outreach; increasing knowledge
about the spread and biology of Elodea in Alaska; developing effective control
treatments; learning from case studies of Elodea introductions around the world;
and implementing constraints or regulations aimed to prevent continued spread
into new waterways. With a concerted, statewide effort, we hope to minimize
damage to Alaska’s freshwater ecosystems from Elodea and other aquatic invaders.
The Alaska Weed Management ARRA Project — Employing
Alaskans
Joan Hope, Alaska Association of Conservation Districts

The Alaska Weed Management American Recovery and Reinvestment Act (ARRA)
Project originated as a cooperative agreement between Region 10 Forest Health
Protection and the Alaska Association of Conservation Districts. In addition to dedicating
our efforts to invasive plant outreach and eradication, we also focused on jobs,
providing participants with training, experience and skills that would enable them to
continue their employment in this field after the ARRA funding was spent. We wanted
to increase the capacity of Alaskans to respond to invasive plant issues.

In total, 18 people were employed during the course of the project. These included 13
Invasive Plant Coordinators, who worked in communities around the state for one year,
a three-person summer weed crew, one Project Manager and one Budget
Assistant/Grant      Writer     (fig.    1_Alaska_Weed_Management_Essay.jpg,           fig.
2_Alaska_Weed_Management_Essay.jpg). Of the 15 full-time employees, eight were
unemployed at the time of hiring, and another four were underemployed. As the project
began to wind down, we provided grant-writing training to all of these employees, and
encouraged them to pursue new funding sources to continue their invasive plant work
in Alaska. Our goal was to offset the jobs that would be lost at the end of the project by
helping participants to find and create future employment opportunities.

The project was successful beyond our expectations. Over 5,000 acres were surveyed
for invasive plant infestations, thousands of new infestation records were added to the
Alaska        Exotic        Plant       Information        Clearinghouse      database
(http://aknhp.uaa.alaska.edu/maps/akepic/ ), and approximately 1,000 bags of weeds
were pulled. In addition, greater than 100 acres were treated by various means,
including pulling, digging, spraying, burning, tarping and whacking. Outreach and
education efforts provided more than 2,000 students and 5,000 adults with information
about invasive plants, their effects on Alaska’s native ecosystems, and how to control
them, and nearly 1,000 volunteers were recruited to help with remediation projects. We
established relationships in numerous rural villages, including two that are now
developing their own Tribal Conservation Districts, Kwethluk and Tyonek. We provided
training and remediation plans in several Yukon-Kuskokwim Delta villages and in the
community of Tyonek. Invasive plant management plans were generated by our team
for numerous private and public property owners and managers, including a community
garden, several municipalities, an arboretum, and a number of farmers.
When the year of funding was over, one Coordinator took a job working with farmers in
Montana, Wyoming, and Idaho to develop more efficient irrigation systems. Two are
now employed by the Ekuk and Napaimute village councils, working as environmental
coordinators. Two others obtained multi-year funding through the Alaska Sustainable
Salmon Fund (AKSSF, a NOAA-funded program) to manage invasive plants on several
streams in the Matanuska-Susitna River Valley through the Palmer Soil and Water
Conservation District. One is working on Alaska’s first known introduced freshwater
aquatic weed, Elodea, with grant funding obtained from the AKSSF. Another secured
grant funding through USDA Forest Service, US Fish and Wildlife Service, and AKSSF to
work on invasive plant issues in the Juneau area. One is beginning a new project on
weed management in underserved areas of southeast Alaska, and another obtained a
grant through AKSSF to work on invasive plant projects near salmon-bearing waterways
in Cordova. The Coordinator in Seward is working with the Resurrection Bay
Conservation Alliance on invasive plant issues in that region. In Kenai, the Coordinator
that had worked as an invasive pest management technician for the Cooperative
Extension Service (CES) prior to the ARRA project was promoted and retained full-time
by the CES.

Our Budget Assistant now works part-time for the Palmer Soil and Water Conservation
District (SWCD) and is developing her own grant-writing business. As the manager of the
project, I have been retained by Alaska Association of Conservation Districts to seek
funding for, and manage, new invasive plant projects. Lastly, as a result of the ARRA
project’s efforts in western Alaska, the Bristol Bay Native Association created five new
seasonal positions to work in villages in western Alaska. And a multi-year grant was
awarded by the Western Alaska Land Conservation Cooperative to AACD to fund
outreach and invasive plant surveys in 26 previously unsurveyed western Alaskan
villages. This will create three or more seasonal jobs in 2012 and 2013.

In total, our work on the Alaska Weed Management ARRA project led to 13 full-time and
more than eight seasonal jobs. We believe that we have fully satisfied the Recovery Act
goal of providing training and experience to enhance future employment opportunities.
This project also allowed us to make tremendous strides with respect to increasing the
capacity of Alaskans to respond to the threats and challenges of invasive plants.

				
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